Conventional navigation devices have a destinations database with addressable destination objects representative of cities and ZIP codes. The devices further provide a user interface for searching the destinations database. FIG. 1 illustrates such a user interface in the exemplary form of a Graphical User Interface (GUI) 10 displayed on a touch screen of a navigation device.
When searching for a particular city as destination for route guidance, a user operating the navigation device inputs the city name via a keyboard 20 presented on the GUI 10. The letters input by the user are displayed in a display line 30, and the navigation device performs a background search to present city names including the letter sequence input thus far on a display section 40 for user selection. As an alternative to a city name, the ZIP code of a city may be entered as well during the destination search.
In addition to city destinations, modern navigation devices also offer so-called Points Of Interest (POIs) and user programmed target points as destinations for route calculation and route guidance. POIs (e.g., particular sights, restaurants, gas stations, and so on) can be searched and selected in the same manner described above by entering letters via the keyboard 20. User programmed target points can be input via their geographical coordinates or by marking them for example on a map displayed on the touch screen.
It has been found that it is currently not possible to search for all graphical objects typically presented during route guidance on a navigation screen of the navigation device. For example, while certain geographical areas such as woods, lakes, states and seas along a guided route are visually displayed by the navigation device, the user can presently not search for a specific geographical area such as “Loch Ness” or “Blackwood Forest” as destination using, for example, the GUI 10 illustrated in FIG. 1. Rather, the user has to search for a city (that needs to be known to him or her) in the vicinity of the area of interest. Alternatively, the user has to explicitly mark the area of interest as destination point on a map displayed on the touch screen. Both approaches can get time-consuming and error-prone.